1. Field of the Invention
The present invention relates to a method, an apparatus, and a program for processing information and, in particular, to a method, an apparatus, and a program that allow a decrypting apparatus to properly carry out a decrypting process using meta data even when an error has occurred during transmission of the meta data from an encrypting apparatus to the decrypting apparatus.
2. Description of the Related Art
In recent years, an encryption method has been proposed in which stream data including a plurality of successive units of data is sequentially encrypted on a unit-by-unit basis and a key used for encrypting each of the units of data is changed according to a predetermined rule (refer to, for example, Japanese Unexamined Patent Application Publication No. 2003-143548).
In addition, the development of an encrypting apparatus that encrypts stream data according to such an encryption method and generates meta data including a plurality of keys used for encrypting the stream data and update information for identifying the timings of updating the keys has started.
Furthermore, the development of a decrypting apparatus that decrypts data encrypted using such an encrypting apparatus by using the meta data generated by the encrypting apparatus has started.